In a QFN package, after the entire lead frame on which plural semiconductor chips are mounted is sealed with resins, singulation is performed with a dicing device to form individual packages. The dicing device has a rotating blade, and by moving the blade along the cutting line, the leads exposed on the inner surface of the package and the resin are cut simultaneously. However, when the moving velocity of the blade reaches, e.g., 30 mm/s or higher, numerous metal burrs are generated on the cutting plane of the lead frame. Said burrs are generated not only in the direction in which the blade is moved (i.e., the cutting direction), but also in the plate thickness direction of the lead frame.
FIG. 8 is a photograph of a cutting plane that was formed by moving the blade at a velocity of 30 mm/sec. The white portions correspond to the cutting plane of the lead, while the black portion corresponds to the cutting plane of the resin. As can be seen from this photograph, burrs appear in the cutting direction. Because the clearance between the leads is small, the burrs in the cutting direction lead to short-circuit problems, such as solder bridges, etc., when leads with a narrow pitch are assembled on a wiring substrate. Also, because the burrs in the plate thickness direction of the leads protrude from the inner surface of the package, the planarization (flatness) of the QFN package will be poor, and when it is assembled on the wiring substrate, the connections to the lands of the wiring substrate will also be poor, which is undesirable.
On the other hand, in order to suppress generation of burrs, the cutting velocity of the blade may be reduced. However, this drops the singulation throughput. The technologies disclosed in said Patent References 1 and 2 suggest nothing about improving the singulation throughput.
The purpose of the present invention is to solve the aforementioned problems of the prior art by providing a semiconductor device manufacturing method characterized by the fact that the speed of singulation of packages by means of dicing is increased, while suppressing the generation of burrs.